A common way of analyzing the motion of objects in
physics labs is to perform a ticker
tape analysis. A long tape is attached to a
moving object and threaded through a device that places a
tick upon the tape at regular intervals of time – say every
0.1 second. As the object moves, it drags the tape through
the "ticker," thus leaving a trail of dots. The trail of
dots provides a history of the object's motion and is therefore
a representation of the object's motion.
The distance between dots on a ticker tape
represents the object's position change during that time
interval. A large distance between dots indicates that the
object was moving fast during that time interval. A small
distance between dots means the object was moving slow
during that time interval. Ticker tapes for a fast-moving and
a slow-moving object are depicted below.
The analysis of a ticker tape diagram will
also reveal if the object is moving with a constant velocity
or with a changing velocity (accelerating).
A changing distance between dots indicates
a changing velocity and thus an acceleration.
A constant distance between dots represents a constant
velocity and therefore no acceleration. Ticker tapes for
objects moving with a constant velocity and an accelerated
motion are shown below.
And so ticker tape diagrams provide one more means of
representing various features of the motion of objects.
Check Your
Understanding
Ticker tape diagrams are sometimes referred to as oil
drop diagrams. Imagine a car with a leaky engine that drips
oil at a regular rate. As the car travels through town, it
would leave a trace of oil on the street. That trace would
reveal information about the motion of the car. Renatta Oyle
owns such a car and it leaves a signature of Renatta's
motion wherever she goes. Analyze the three traces of
Renatta's ventures as shown below. Assume Renatta is
traveling from left to right. Describe the characteristics of
Renatta's motion during each section of the diagram. Use the
pop-up menu to check your answers.
